At present, a prevailing technology and method for preparing organic light emitting diodes (OLED, Organic Light Emitting Diode) is an evaporation method, in which organic materials with small molecules are heated in a vacuum cavity, and are sublimated or melted and gasified into steam, and then deposited on a glass substrate through openings in a metal mask.
When a display device of a display apparatus is manufactured, an evaporation crucible is usually used. The evaporation crucible has a containing means. The evaporation crucible is placed in an evaporation source (for example, a point source). A crucible cap is mounted at the opening of the containing means and is provided with evaporation apertures. Its operation principle is as follows. The evaporation material comprising organic materials is placed in the containing means of the evaporation crucible. The evaporation crucible is placed into the evaporation source, and the evaporation source heats the evaporation crucible so that the gasified evaporation material is uniformly evaporated out of the evaporation apertures of the crucible cap. A sensor for detecting the evaporation speed of the gasified evaporation material is disposed above the crucible cap. The sensor feeds back the detected signal to the evaporation source so that the evaporation source controls intensity of heating the evaporation crucible based on the evaporation speed of the evaporation material.
In the OLED evaporation apparatus, evaporation material is placed in the crucible, and the crucible is placed in the evaporation source. The crucible is heated by a heater within a heating source and the evaporation material is evaporated in a vacuum environment. In the current OLED evaporation apparatus, the crucible is placed in the evaporation source in a stationary manner. Since that peripheries of the crucible are uniformly heated cannot be completely guaranteed, as illustrated in FIG. 1, there is a phenomenon that the material within the crucible is not heated uniformly which causes an unstable evaporation process.